1. Field of the Invention
The present invention is in the field of desulfurizing a flue gas from a firing system by means of bonding the gaseous sulfur oxides to calcium.
2. Description of the Prior Art
As a result of legal provisions of Germany and other countries, and particularly due to the "Technical Directive for Maintaining the Purity of Air" operators of large scale industrial firing systems such as, for example, power plants or cement making plants are obliged not to exceed certain limiting values of particulate or gaseous pollutants (for example, dust, carbon monoxide, sulfur dioxide, nitrogen oxides) in the exhaust gases emitted to the atmosphere.
It is therefore necessary to operate exhaust gas cleaning systems, particularly for de-dusting and desulfurization of the exhaust gas. Since large scale industrial firing systems usually produce extremely large quantities of flue gas with relatively low concentrations of pollutants, correspondingly large exhaust gas cleaning systems are required. These involve high investment cost, subsequently high capital cost, high operating cost, maintenance cost, and waste disposal cost. These costs must be added to the product produced. Therefore, it becomes necessary economically as well as competitively to reduce the pollutants not only for economic reasons but for safety reasons. It becomes necessary to employ optimal means which are expanded, or relatively available and to carry out such measures to yield the greatest improvement in exhaust gas cleaning technology, and thus, improvements in the affected environment.